Allow the environment to enable Podman on the overcloud
Allow the environment to enable Podman on the overcloud

It modifies environments/podman.yaml that overrides the default
ContainerCli so we deploy podman instead of Docker on the Overcloud.

Change-Id: Ia6d5354d120fc2e76d6d9c4e41b3f637ad152ecd

dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates